Department of Plant Systems Biology, Ghent University, 9052 Gent, Belgium.
Nature. 2012 Apr 15;485(7396):119-22. doi: 10.1038/nature11001.
The phytohormone auxin acts as a prominent signal, providing, by its local accumulation or depletion in selected cells, a spatial and temporal reference for changes in the developmental program. The distribution of auxin depends on both auxin metabolism (biosynthesis, conjugation and degradation) and cellular auxin transport. We identified in silico a novel putative auxin transport facilitator family, called PIN-LIKES (PILS). Here we illustrate that PILS proteins are required for auxin-dependent regulation of plant growth by determining the cellular sensitivity to auxin. PILS proteins regulate intracellular auxin accumulation at the endoplasmic reticulum and thus auxin availability for nuclear auxin signalling. PILS activity affects the level of endogenous auxin indole-3-acetic acid (IAA), presumably via intracellular accumulation and metabolism. Our findings reveal that the transport machinery to compartmentalize auxin within the cell is of an unexpected molecular complexity and demonstrate this compartmentalization to be functionally important for a number of developmental processes.
植物激素生长素作为一种重要的信号分子，通过在特定细胞中局部积累或耗尽，为发育程序的变化提供时空参考。生长素的分布取决于生长素的代谢（合成、结合和降解）和细胞内生长素的运输。我们通过计算机筛选出一种新的生长素运输促进因子家族，称为 PIN-LIKES（PILS）。在这里，我们通过确定细胞对生长素的敏感性，说明了 PILS 蛋白在生长素依赖的植物生长调控中是必需的。PILS 蛋白调节内质网中细胞内生长素的积累，从而影响生长素用于核生长素信号的可用性。PILS 活性影响内源性生长素吲哚-3-乙酸（IAA）的水平，可能是通过细胞内积累和代谢。我们的研究结果表明，将生长素在细胞内分隔开的运输机制具有出乎意料的分子复杂性，并证明这种分隔对于许多发育过程具有重要的功能。
